title: pH-dependent antibacterial effects on oral microorganisms through pure PLGA implants and composites with nanosized bioactive glass.
abstract: Biomaterials made of biodegradable poly(α-hydroxyesters) such as poly(lactide-co-glycolide) (PLGA) are known to decrease the pH in the vicinity of the implants. Bioactive glass (BG) is being investigated as a counteracting agent buffering the acidic degradation products. However, in dentistry the question arises whether an antibacterial effect is rather obtained from pure PLGA or from BG/PLGA composites, as BG has been proved to be antimicrobial. In the present study the antimicrobial properties of electrospun PLGA and BG45S5/PLGA fibres were investigated using human oral bacteria (specified with mass spectrometry) incubated for up to 24 h. BG45S5 nanoparticles were prepared by flame spray synthesis. The change in colony-forming units (CFU) of the bacteria was correlated with the pH of the medium during incubation. The morphology and structure of the scaffolds as well as the appearance of the bacteria were followed bymicroscopy. Additionally, we studied if the presence of BG45S5 had an influence on the degradation speed of the polymer. Finally, it turned out that the pH increase induced by the presence of BG45S5 in the scaffold did not last long enough to show a reduction in CFU. On the contrary, pure PLGA demonstrated antibacterial properties that should be taken into consideration when designing biomaterials for dental applications.
authors.affiliation: Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland.
authors.forename: Nora
authors.initials: N
authors.lastname: Hild
authors.forename: Pune N
authors.initials: PN
authors.lastname: Tawakoli
authors.forename: Jonas G
authors.initials: JG
authors.lastname: Halter
authors.forename: Bärbel
authors.initials: B
authors.lastname: Sauer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Buchalla
authors.forename: Wendelin J
authors.initials: WJ
authors.lastname: Stark
authors.forename: Dirk
authors.initials: D
authors.lastname: Mohn
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development; D002516:Ceramics / Q000737:chemistry*; D015169:Colony Count, Microbial; D005898:Glass / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D020007:Implants, Experimental; D019344:Lactic Acid / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D008970:Molecular Weight; D009055:Mouth / Q000382:microbiology; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D012996:Solutions; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D012996:Solutions; C425330:bioactive glass 45S5; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid
keywords: Antimicrobial; Bioglass; Electrospinning; Implant; Nanoparticles